error[E0277]: the trait bound `dyn Foo<(char,), Output = ()>: Eq>` is not satisfied --> $DIR/unboxed-closure-sugar-equiv.rs:44:11 | LL | dyn Foo(char) >(); | ^^^^^^^^^^^^^ the trait `Eq>` is not implemented for `dyn Foo<(char,), Output = ()>` | note: required by a bound in `eq` --> $DIR/unboxed-closure-sugar-equiv.rs:16:28 | LL | fn eq>() { } | ^^^^^ required by this bound in `eq` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0277`.